OpenAI Codex app looks beyond the IDE, devs ask why Mac-only?

OpenAI has released the Codex app, designed for multi-tasking with agents, but although built with Electron it is currently Mac-only, raising complaints from developers.

According to the introductory post, traditional IDEs or terminal-based tools are unsuitable for the way developers now work, presuming they have bought into the notion that AI does most of the coding. "Developers are now orchestrating multiple agents across projects," the company said. 

Codex is OpenAI’s software engineering agent, introduced in April 2025 as a CLI (command-line interface) tool. Further variants include a side-bar in ChatGPT, and IDE extensions for Visual Studio Code (VS Code), Cursor, Windsurf and JetBrains IDEs.

The Codex app enables developers to create and manage multiple projects, each with one or more agents running in separate threads. Features include scheduled automations, the ability for agents to run locally or remotely, support for Git worktrees so agent-generated code is separate from the main branch, agent skills for giving Codex specialist instructions, a built-in terminal, and sandboxing to control which directories and network access Codex can use.

Integration with the CLI and IDE extensions means that the Codex app shares settings regarding which MCP (model context protocol) servers it can use and their configuration. It is easy to switch away from the Codex app to work in an IDE when needed.

The Codex app looks like OpenAI’s answer to Anthropic’s Claude desktop app, currently in preview. Early experiences with the Codex app vary but the concept is welcome. OpenAI has made Codex App work with even the free tier for ChatGPT, for an initial period.

A common refrain in the first feedback is that the Codex app is not yet available for Windows or Linux, though both are promised. "Mac only. Again. Apple is great but this is OpenAI devs showing their disconnect from the mainstream," said one dev. A member of the OpenAI team replied that "the team actually built the app in Electron specifically so we can support Windows and Linux as well." The hitch, according to another comment, is that "it's taking us some time to get really solid sandboxing working on Windows, where there are fewer OS-level primitives for it."

The issue is linked to the experimental Windows sandbox described here, and which has limitations. "When using the Windows sandbox, Codex scans for folders where Everyone has write access and recommends that you remove that access," the docs state, showing the complexity of this approach.

Some Mac developers are also unhappy, because OpenAI is using Electron rather than a native code application. Electron is a cross-platform framework based on embedding the Chromium web browser and Node.js runtime, and while it is effective for cross-platform support, it uses more memory than native code. The popularity of Electron, which is also used by other developer tools including VS Code, Docker Desktop and Slack, means that multiple instances can run at once, adding to the resource burden.